Method and apparatus for controlling a yarn-winding machine having an automatic knotting device



1966 HANS-GUNTER WILMS ETAL 3,

METHOD AND APPARATUS FOR CQNTROLLING A YARNWINDING MACHINE HAVING ANAUTOMATIC KNOTTING DEVICE Filed June 1, 1964 2 Sheets-Sheet 1 I Q c3 D 69 HANSGUNTER WILMS ETAL 3,289,957

METHOD AND APPARATUS FOR CONTROLLING A YARN-WINDING MACHINE HAVING ANAUTOMATIC KNOTTING DEVICE Filed June 1, 1964 2. Sheets-Sheet 2 FIG. 4

United States Patent R a, 14 Claims. (Cl. 24235.6)

Our invention relates to a method and apparatus for controlling ormonitoring a yarn-winding machine of the type that has an automaticknotting device.

It is generally known that faulty knots can occur in a yarn-windingmachine with an automatic knotting device due to a great variety ofcauses. A fault can sometimes take place, for example, by the knottingof a double yarn in which a doubled yarn length, for example in the formof a loop, instead of a single yarn length is inserted in the knottingdevice from one or both sides thereof. In order to eliminate suchfailures or faults for the most part, it has been disclosed in ac-opending application whereof one of us is a co-inventor, namelyapplication Serial No. 307,077, filed September 6, 1963, now Patent No.3,220,- 758, to provide the :knotting device with a control mechanismwhich determines the number of yarn ends that are inserted in theknotte-r.

Another cause of failure of the knotting operation is that the knots maynot be pulled together sufficiently firmly. It is, of course, known thatin the formation of a so-called fishermans knot, two individual knotsare first formed and are subsequently drawn together. If theseindividual knots are not drawn together perfectly to form a common knot,a gap occurs between both individual knots subsequently causing theknots to loosen. It is, furthermore, known that when forming other typesof knots, as for example a weavers knot, it is possible that the knotmay not be sufficiently tightened. This can also cause the knot toloosen thereafter. In order to eliminate these disadvantages, a devicehas also been provided which tests the completed knots for durability,for example by subjecting them to an increased tension.

It is evident that for the great variety of possible knotting failuresor faults that can occur, a correspondingly great number of inspectionmethods and devices have been developed which entail a rather greatexpenditure.

It is accordingly an object of our invention to avoid the disadvantagesof known devices and also to improve the method and apparatus forcontrolling and monitoring the knotting operation so that the expensethereof can be reduced.

To this end and in accordance with our invention we provide a method andapparatus for controlling or monitoring a yarnwinding machine having anautomatic knotting device by means of which the dimensions of thecompleted knot are measured and when the measured dimensions deviatefrom a desired standard value, the faulty yarn connection or tie issevered and discarded.

Contrary to the methods and apparatuses known to date wherein theconditions that can produce a knot and that do in fact produce a knotare inspected or controlled, in accordance with our invention, thecompleted knot is monitored to determine if its dimensions correspond toa predetermined standard value, since a proper knot can be realized onlyin such case. If the knot should vary in dimension from the standardvalue, then no proper knot could possibly have been realized but rathera faulty knot must have been formed [for example as a double yarn knotor a tie in which the knot is not tightened with suiiicient firmness. Inall the cases in which the dimensions of the completed knot deviate fromthat of a standard value, the faulty yarn tie is severed so that a newknotting attempt can be carried out culminating eventually in most casesin a proper knotting operation.

The tightness or the diameter as well as the volume of the knot, forexample, can be used as the dimension of the completed knot that is tobe measured. An especially certain method is provided when the textilemass of the knot is measured.

Forcarrying out the method of our invention, a yarn winding machine canbe employed in which a measuring device for determining the dimension ofa knot can be provided at the knotting device or in the path of the yarnas it passes through the winding machine behind the knotting device, andwhich is operatively connected with a. yarn severing device.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention has been illustrated and described as a methodand apparatus for controlling a yarnwinding machine having an automaticknotting device, it is nevertheless not intended to be limited to thedetails shown since various modifications and structural changes may bemade therein without departing from the spirit of the invention andwithin the scope and range of the equivalents of the claims.

The construction and method of ope-ration of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description when read in connection withthe accompanying drawings, in which:

FIG. 1a shows a conventionally formed knot and FIG. 1b shows a so-calleddouble yarn knot or faulty knot.

FIG. 2 is a cross-sectional view of a knotter head diagrammaticallyillustrating the position of the yarn at three different moments.

FIG. 3 shows the knotter head of FIG. 2 with a device for capacitivelydetermining the textile mass of the knot in accordance with ourinvention; and

FIG. 4 is a circuit diagram and associated elements for operating thedevice shown in FIG. 3.

Referring now to the drawings and initially to FIG. 1a, there is shown aknotted yarn in which a conventional knot has been formed. In FIG. 1bthere is shown a knot, however, which during knotting has formed adouble yarn. It is obvious that the size of the knot in FIG. 1b isconsiderably larger than the conventional knot of FIG. 1a. The knot withthe double yarn differs not only in thickness or diameter but also involume and in the textile mass as compared to the conventional knotshown in FIG. 1a.

The knotter head of a knotting device 1 such as disclosed in US. PatentsNos. 2,981,559 and 3,110,511 and described in the aforementionedapplication Serial No. 307,077, is shown in FIG. 2, as well as thelocation of the yarn at three different moments F F F At the moment whenthe yarn is located at F the knot has just been tied and has beentightened by the tensioning member 11 of the knotter I. The upper andlower yarn ends, as seen in FIG. 2, are gripped at the locations 12 and13 in yarn clamps which are of the general type disclosed in theaforementioned US. Patents Nos. 2,981,559 and 3,110,511 and inapplication Serial No. 306,265 to Albert Pesch, filed September 3, 1963,now Patent No. 3,188,125. The dot and dash line F shows the finallocation of the yarn after the winding station of the yarn windingmachine of the type, for example, shown and described in theaforementioned application Serial No. 306,265 has been operating for aperiod of time and the yarn is stressed along its entire length. Theintermediate position at the moment F shows the location of the yarndirectly after the winding station has been started up and the yarn hasbeen freed by the clamping means 12, 13. As shown in the embodiment ofFIG. 2, the knot K has been drawn out of the knotter head of theknotting device 1 and has reached a mechanical yarn cleaner 2 ofconventional construction located between the knotting device and atake-up spool (not shown). The cleaner 2 is provided with a slot thathas been adjusted to a width through which a conventional knot canreadily pass. 'When a knot has been formed with a double yarn however,as is indicated by the yarn F the diameter of the knot is so large thatthe knot cannot pass through the slot of the mechanical yarn cleaner.The yarn can, therefore, not be wound or drawn any further andconsequently breaks.

The employment of a photoelectric device for monitoring the knot has anadvantage over the aforedescribed mechanical yarn cleaning device andalso of known electro-mechanical types of yarn cleaners, in that thethickness of the knot can be inspected in a comparatively simple mannerand, furthermore, in addition to determining if the knot is too thick,such as for example when a double yarn knot has been formed, it can alsodetermine when the knot is too thin due to being improperly tied. Thereis difficulty, however, in inspecting the knot with a photoelectricdevice because for example, the diameter of a double yarn knot is onlyabout 1.3 times that of a normal knot, i.e., the increase in thicknessover that of a normal knot is relatively small. Nevertheless, in manycases such optical measurement of the yarn is completely suflicient andhas an important advantage in that it is of a relatively simpleconstruction as against the considerably more complex construction ofthe hereinafter described device.

An absolutely certain method of testing the knot in accordance with afurther aspect of our invention is by measuring the textile mass ormaterial of the knot. Although the diameter of a double yarn knot may beonly about one third larger than that of a normal knot, the amount oftextile material contained in a double yarn knot is substantially twiceas large as that in a normal knot. Furthermore, the mass of textilematerial con tained in the knot is nearly independent of the tension ofthe yarn by means of which the knotting operation is carried out. Thedetermination of the textile mass of the knot thus provides aconsiderably greater capability of distinguishing between ordinarilytied knots and faulty knots as compared with the determination of theknot thickness.

In accordance with a further aspect of our invention, we provide anelectronic yarn cleaner for ascertaining the textile mass of the knot.This electronic yarn cleaner consists of a capacitive measurementbridge, whose measuring capacitors are as long as the knot in the axialdirection of the yarn. With this measurement device, the dielectricconstant of the air between the electrodes of the capacitor is replacedby that of the textile mass. Thus it is advantageous for the measurementcapacitor in the yarn path direction to be approximately as long as theknot so as notalso to include in the measurement the projecting yarnends of the knot. The relative size of the electrodes 31a, 31b of themeasuring capacitor 31 as compared to the knot itself can be seen inFIGS. 1a and lb. If such a device is driven with the usual measuringfrequency of from to about 50 mHz. (megacycles), the capacitivereactance becomes very great for such a small measuring capacitor sothat the device is relatively sensitive to stray fields. It is',therefore, advisable in such a case to employ a higher measuringfrequency, for example 500 mHz., so that the capacitive reactance of themeasuring capacitor is closer to one tenth that of the device that isdriven with the usual measuring frequency. A high measuring frequency ofthis type, furthermore, has the advantage of permitting accuratemeasurement of even small changes in capacitance. The measuringfrequency proper can be produced relatively simply with transistors byconventional circuitry. Such a measurement frequency generator can belocated directly near the sensing means or capacitor electrodes becauseof its small measurements so that troublesome high frequency cable leadsare unnecessary. The measuring device proper is represented in thisapplication for example by a conventional capacitance measuring bridge.It is, however, also possible to detune a tuned resonance circuit by thetextile mass and to employ the changed frequency or the changedresonance frequency as a measuring signal.

A device for capacitively determining the textile mass of the knot isshown schematically in FIG. 3. A yarn F is shown in FIG. 3 as havingjust been released from the clamps 12, 13 of the knotter head 1 so thatthe knot has moved upwardly, as shown in FIG. 3, in the direction towarda take-up spool 10 of the Winding station. The capacitance measuringdevice 3 is located above the knotter head 1, and includes a measuringcapacitor 31 and carries a severing device 32 controlled in a suitablemanner by the measurement. When the textile mass of the knot passing thecapacitor 31 deviates from a predetermined standard value adjusted inthe capacitance measuring device 3, the difference in capacitance ofcapacitor 31 with respect to the standard value can actuate the severingdevice 32 to sever the yarn as described hereinafter with respect toFIG. 4. It is immaterial whether the knot has a mass that is greaterthan or less than the predetermined value. Whereas only too thick i.e.double knots, are able to be eliminated by devices for the mechanicalmeasurement of the yarn such as is shown in FIG. 2 and described in theforegoing, and also by devices which electro-mechanically measure theyarn, with electronic measurement of the yarn as well as with thedescribed photoelectric measurement of the knot, on the other hand, aknot thatis too thin can also be eliminated.

FIG. 4 schematically shows the capacitance measuring bridge 33 which isof conventional construction, energized by an A.C. source and connectedto an indicator device 34 of the galvanometer type having anelectrically conducting centrally pivoted arm 35. When the yarn length Fof normal thickness passes between the electrodes of the capacitor 31 ofthe bridge 33, the arm 35 assumes the position illustrated in FIG. 4.When a thin tie is made in the yarn and passes between the electrodes ofthe capacitor 31 the change in dielectric constant between theelectrodes increases the capacitance, and the arm 35 is pivotedclockwise so that the contact ends thereof engage the fixed contacts34a, 34b to complete the circuit 36 and energize the relay 32a whichactuates the severing device 32 to sever the faultily tied yarn F Whenthe knot K conforms in textile mass with a predetermined standard value,the arm 35 is pivoted to the dotted line position shown in FIG. 4 inwhich the secondary circuit 36 is broken and the severing device 32 isinoperative.

When the knot passing through the capacitor 31 is a faulty double knotor greater than the desired textile mass, the arm 35 is pivoted stillfurther clockwise so that it engages the fixed contacts 340 and 34d tocomplete the secondary circuit 36 to actuate the severing device and cutthe yarn F It is of course understood that the device 34 can for examplebe replaced by a parallel system of relays which are energizable atdifferent voltages to actuate the severing device 32. Thus circuit 36would be energized only at a range of voltages between the voltagesacross the bridge 33 when the yarn P of standard thickness and the knotK of standard textile mass pass through the capacitor 31, and at avoltage in excess of that for a standard knot K.

As can be visualized from FIG. 2, the knotting device 1 is located inthe winding machine in such a way that the yarn runs relatively rapidlyout of reach of the knotting device after the knot is tied and thewinding station has been started up, and assumes the position F For amechanical yarn cleaner as shown in FIG. 2, this appearance can beaccepted as reasonable since the knot reaches the cleaner 2 faster thanthe yarn reaches the position F For the electronic measurement of theknot shown in FIG. 3 and also for many other measuring means, forexample particularly a photoelectric sensing device, however, the yarnmust pass through the measuring apparatus at a quite specific locationsince otherwise false measurements could take place. In order to insurethe desired path location of the yarn, in the embodiment of FIG. 3 thereis located in the yarn path behind the measuring device, a guide member4 which guides the yarn through the measuring device shortly after theknot has been formed. As soon as the knot has passed through themeasuring device 3 or has passed the guide member 4, the latter isremoved so that the yarn can assume the esired position P of FIG. 2. Theremoval of the guide member 4 can take place for example in a well knownmanner by pivotally mounting the guide member 4 and controlling themovement of the guide member 4 with means known in the art, for exampleby providing suitable linkages for actuating the guide member from thecontrol cams of the winding machine or from the control cams of theknotting device or from the measuring impulse of the measuring device 3or from an adjustable time period or also by the knot K engaging theguide member 4 along its entire length.

We claim:

1. Method of monitoring a knot formed by tying a pair of yarn lengthstogether with a knotting device of an automatic winding machine whichcomprises momentarily subjecting the tied yarn to a dimension-measuringdevice for measuring a dimension of the knot, and severing the tied yarnlengths when the measured dimension deviates from a. predeterminedvalue.

2. Method of monitoring a knot formed by tying a pair of yarn lengthstogether with a knotting device of an automatic winding machine whichcomprises momentarily subjecting the tied yarn to a thickness-measuringdevice for measuring the thickness of the knot, and severing the tiedyarn lengths when the measured thickness of the knot deviates from apredetermined standard thickness.

3. Method of monitoring a knot formed by tying a pair of textile yarnlengths together with a knotting device of an automatic yarn windingmachine which comprises momentarily subjecting the tied yarn to amass-measuring device for measuring the textile mass of the knot andseparating the tied yarn lengths when the measured textile mass of theknot deviates from a predetermined standard value.

4. In a yarn winding machine having a knotting device for tying a knotwith a pair of yarn ends, means for measuring a dimension of a knot tiedby the knotting device, means for momentarily placing the tied textileyarn in a position in which it is subjected to said measuring means, andmeans actuated by said measuring means for separating the yarn ends whenthe measured dimension deviates from a predetermined value.

5. In a yarn winding machine having a knotting device for tying a knotwith a pair of yarn ends, means for measuring a dimension of a knot tiedby the knotting device and comparing it to a predetermined value, meansfor momentarily placing the tied textile yarn in a position in which itis subjected to said measuring means, and severing means responsive tosaid measuring means for severing the tied yarn ends when the measureddimension of the knot deviates from said predetermined value.

6. In an automatic yarn winding machine including a knotting device fortying together a yarn end from a supply coil with a yarn end from atake-up spool, the knotting device being located intermediate thetake-up spool and the supply coil and adjacent a path of the tied yarnextending between the supply coil and the take-up spool, a measurementdevice located between the knotting device and the take-up spool acrossthe path of the tied yarn for measuring at a measuring location thereofadimension of a knot tying the yarn ends together, means for momentarilyplacing the tied yarn in a position in which it is subjected to saidmeasurement device, and a severing device operatively connected withsaid measurement device and located adjacent the yarn path between themeasuring location of said measurement device and the take-up spool,said measurement device being responsive to deviation of the measureddimension of the knot from a predetermined standard value for actuatingsaid severing device to sever the tied y-arn ends.

7. In an automatic yarn winding machine including a knotting device fortying together a yarn end from a supply coil with a yarn end from atake-up spool to form a continuous yarn length movable in a path fromthe supply coil to the take-up spool, the knotting device being locatedadjacent the yarn path and intermediate the take-up spool and the supplycoil, means located adjacent the yarn path and knotting device and thetake-up spool for determining a dimension of the knot tied by theknotting device and for severing said yarn length when the determineddimension deviates from standard value, and means for momentarilyplacing the tied yarn in a position in which it is subjected to saidlast-mentioned means.

8. Yarn winding machine according to claim 7 wherein said meanscomprises a yarn cleaner having a slot of preetermined width locatedtransversely to the yarn path and the yarn length is guidingly movablethrough said slot along the yarn path, the knot tied in said yarnlength, when of a thickness smaller than the width of said slot, beingpassable through said cleaner whereby the yarn length is continuouslywound on the take-up spool, and when of a thickness greater than thewidth of said slot, being obstructed by said yarn cleaner whereby theyarn length is prevented from being wound on said take-up spool and isbroken.

9. In an automatic yarn winding machine including a knotting device fortying together a yarn end from a supply coil with a yarn end from atake-up spool to form a continuous yarn length movable in a path fromthe supply coil to the take-up spool, the knotting device being locatedadjacent the yarn path and intermediate the take-up spool and the supplycoil, electronic measuring means located adjacent the yarn path andbetween the knotting device and the take-up spool for determining at ameasuring location the textile mass of the knot tied by the knottingdevice, means for momentarily placing the tied yarn in a position inwhich it is subjected to said measuring means, and severing meansoperatively connected with said measuring means and located adjacent theyarn path between said measuring location and the take-up spool, saidmeasuring means being responsive to deviation of the determined textilemass of the knot from a standard value for actuating said severing meansto sever the yarn length.

10. Yarn winding machine according to claim 9 wherein said electronicmeasuring means comprises a capacitance measuring bridge including acapacitor having spaced electrodes, the yarn path extending between saidelectrodes.

11. Yarn winding machine according to claim 10, said capacitor having apair of electrodes with spaced opposing faces, the yarn length beingmovable along the yarn path between said electrode faces, the length ofsaid faces in the direction of the yarn path being substantially equalto the length of a knot taken in the axial direction of the yarn length.

12. Yarn winding machine according to claim 10 in-- cluding movablecontact means movable in response to change of capacitance of saidcapacitor for energiz'ing a severing device actuating circuit wheneverthe textile mass of the knot deviates from the standard value, wherebythe yarn length is severed.

13. In an automatic yarn winding machine including a knotting device fortying together a yarn end from a supply coil with a yarn end from atake-up spool to form a continuous yarn length movable in a path fromthe supply coil to the take-up spool, the knotting device being locatedadjacent the yarn path and intermediate the take-up spool and the supplycoil, a measurement device located between the knotting device and thetake-up spool adjacent the path of the yarn length for measuring at ameasuring location thereof a dimension of a knot tying the yarn endstogether, means for momentarily placing the tied yarn in a position inwhich it is subjected to said measurement device, a severing deviceoperable by said measurement device and located adjacent the yarn pathbetween said measuring location and the take-up spool, said measurementdevice being responsive to deviation of the measured dimension of theknot from a predetermined standard value for actuating said severingdevice to sever the tied yarn ends, and a guide member located betweensaid measurement device and said take-up spool for guiding the yarnlength in the yarn path past said measurement device.

14. Yarn winding machine according to claim 12 where- 2 ment with theyarn length when the measured dimension of the knot corresponds to thestandard value.

References Cited by the Examiner UNITED STATES PATENTS 2,936,511 5/1960Wilson 2864 3,063,007 11/1962 Baugh et al. 2864 X 3,106,762 10/ 196-3Riera 28-64 3,110,511 11/1963 Gebald 289-2 X 3,132,407 5/1964 Glastra2864 3,187,568 6/1964 Gonsalves et a1. 2864 3,188,125 6/1965 Pesch 2892FOREIGN PATENTS 1,316,957 12/1962 France.

MERVIN STEIN, Primary Examiner.

DONALD W. PARKER, Examiner.

L. K. RIMRO'DT, Assistant Examiner.

4. IN A YARN WINDING MACHINE HAVING A KNOTTING DEVICE FOR TRYING A KNOTWITH A PAIR OF YARN ENDS, MEANS FOR MEASURING A DIMENSION OF A KNOT TIEDBY THE KNOTTING DEVICE, MEANS FOR MOMENTARILY PLACING THE TIED TEXTILEYARN IN A POSITION IN WHICH IT IS SUBJECTED TO SAID MEASURING MEANS, ANDMEANS ACTUATED BY SAID MEASURING MEANS FOR SEPARATING THE YARN ENDS WITHTHE MEASURED DIMENSION DEVIATES FROM A PREDETERMINED VLAUE.